This invention relates to the use of certain complexes of transition metals with nitrogen-containing polydentate ligands as activators or catalysts for peroxygen compounds, more particularly for bleaching colored stains in the washing of textiles and cleaning of hard surfaces, for example crockery, and to detergents, cleaners and disinfectants containing such activators or catalysts.
Inorganic peroxygen compounds, more particularly hydrogen peroxide, and solid peroxygen compounds which dissolve in water with elimination of hydrogen peroxide, such as sodium perborate and sodium carbonate perhydrate, have long been used as oxidizing agents for disinfecting and bleaching purposes. In dilute solutions, the oxidizing effect of these substances depends to a large extent on the temperature. For example, with H.sub.2 O.sub.2 or perborate in alkaline bleaching liquors, sufficiently rapid bleaching of soiled textiles is only achieved at temperatures above about 80.degree. C. At lower temperatures, the oxidizing effect of the inorganic peroxygen compounds can be improved by addition of so-called bleach activators for which numerous proposals, above all from the classes of N- or O-acyl compounds, for example polyacylated alkylenediamines, more particularly tetraacetyl ethylenediamine, acylated glycolurils, more particularly tetraacetyl glycoluril, N-acylated hydantoins, hydrazides, triazoles, hydrotriazines, urazoles, diketopiperazines, sulfuryl amides and cyanurates, also carboxylic anhydrides, more particularly phthalic anhydride, carboxylic acid esters, more particularly sodium nonanoyloxybenzenesulfonate, sodium isononanoyloxybenzenesulfonate and acylated sugar derivatives, such as pentaacetyl glucose, can be found in the literature. By adding these substances, the bleaching effect of aqueous peroxide liquors can be increased to such an extent that substantially the same effects are obtained at temperatures of only 60.degree. C. as are obtained with the peroxide liquor alone at 95.degree. C. In the search for energy-saving washing and bleaching processes, operating temperatures well below 60.degree. C. and, more particularly, below 45.degree. C. down to the temperature of cold water have acquired increasing significance in recent years.
At these low temperatures, there is generally a discernible reduction in the effect of known activator compounds. Accordingly, there has been no shortage of attempts to develop more effective activators for this temperature range although the results achieved thus far have not been convincing. A starting point in this connection is the use of the transition metal salts and complexes proposed, for example, in European patent applications EP 392 592, EP 443 651, EP 458 397, EP 544 490 or EP 549 271 as so-called bleaching catalysts. In their case, the high reactivity of the oxidizing intermediates formed from them and the peroxygen compound is presumably responsible for the risk of discoloration of colored fabrics and, in extreme cases, oxidative fabric damage. European patent application EP 630 964 describes certain manganese complexes which do not have a pronounced effect in boosting the bleaching action of peroxygen compounds and which do not decolor dyed textile fibers although they are capable of bleaching soil or dye detached from fibers in wash liquors. German patent application DE 44 16 438 describes manganese, copper and cobalt complexes which can carry ligands from a number of groups of compounds and which are said to be used as bleaching and oxidation catalysts.